Can you save a jpeg file in Adobe Photoshop Lightroom? How and What you should do to save it?

In Lightroom, you don't save photos in the traditional sense. Instead, you export photos. You can export photos in various file formats suitable for a wide range of uses.

For example, you can:

• Export photos as JPEGs to share online or as TIFFs for a print publication. 
• Export to a folder on a computer or to an attached or networked drive, such as a Flash drive.
• Burn the photos to a disc after exporting so you can share them on a CD or DVD. 

When you export photos, you create new files that include Develop module adjustments and other changes you’ve made to the photos’ XMP metadata. When exporting, you can choose a photo’s filename, color space, pixel dimensions, and resolution. You can save export settings as presets for reuse.